Introduce IShellView and IFileDialogs so MainWindowVm no longer holds the
concrete window or reaches through MainWindow.Instance, and file pickers are
injectable.
Run Restore off the UI thread like Patch and gate both buttons on IsBusy.
Gate the log commands on a non-empty log.
Move runtime log messages into the locale dictionaries and add the 14 new keys
to all 12 languages.
Track the injected locale dictionary so switching language replaces it instead
of appending a new one each time.
Remove the unused InfoItem control, ToVisibilityInvertedConverter, mw_title and
the popup placeholder title.
kitbyte